This invention relates to field effect transistor (FET) switches for switching a radio frequency (RF) signal path between ON and OFF states and is especially, but not exclusively, suited for use as an RF switch with a high figure of merit, which produces low RF loss and high isolation at high frequencies, or across a wide bandwidth of frequencies.
The increase of electronic applications operating at high frequencies has placed a corresponding demand on the ability of transistor switches to serve as an effective signal path switch with low insertion loss in the ON state and very high impedance in the OFF state. Depending on the design of the specific electronic circuitry or an antenna feed system with a multiple signal feed structure, there is often a need to provide a switch in one or more signal paths in order to control signal flow. With circuitry operating at ultra high frequencies, e.g. 0.3 GHz and above, there exists a need for switching transistors that can provide improved performance.